This paper was produced for the 2019 NAFEMS World Congress in Quebec Canada

Resource Abstract

Ventilation and thermal integration of modern turbofan is one of the main hot topics for new developments. By increasing the pressure ratio, the nacelle and engine compartment becomes smaller with more heat to dissipate but with a limited ventilation capability due to fan duct pressure decrease. This evolution has a significant impact on thermal integration of systems located in the core compartment which is embedded in-between the primary flux and the fan duct. As a consequence, being capable to model such system thermal environment at the very first stage of the engine development allows early identification of thermal integration risk. The adequate thermal protection can then being matured and designed without impacting the development lead time.



This paper deals with a methodology developed to evaluate the thermal behaviour of such environment in order to be capable to predict components temperatures. The approach consists in building a system model with the right physics modelling complexity and fed by numerical and experimental databases. All is a question of compromise between modelling complexity and modelling parameters for which hypothesis have to be done. A too simple model will not be accurate enough; a too complex one will have huge results dispersion due to modelling parameters uncertainty. In this paper, a special attention is paid to key parameters for which specific database are built. The resulting model is standalone, allowing running complete aircraft missions.



A complete model validation has been carried out by comparing results with flight test data. The model accuracy is good enough to be used not only in preliminary development phase, but also all along the development. Because of the extremely quick computation of system modelling, this model is also useful to perform root cause analysis of in-service events.